Defoamers, antifoaming agents, and air release agents are chemical processing aids employed to minimize or eliminate foam in industrial operations. While the terms are often used interchangeably, they employ different mechanisms, so it is worth distinguishing between them.

  • Defoamers are foam control agents which are added to a system to reduce or eliminate foam after it has been formed.
  • Antifoaming agents are foam control agents which are added to a system or formulation to prevent the appearance or emergence of foam.
  • Air release agents help remove entrained gases from a solution and raise them to the surface.

These categories are not strictly mutually exclusive. For instance, many chemical formulations both prevent and destroy foam, in which case they could be classified both as antifoaming agents and defoamers. Additionally, many defoamers have some effect on entrained air, while some air release agents initiate the destabilization process for surface foam.

For the sake of simplicity, the term “defoamer” is generically used as an industry standard when referencing any processing aid designed to control foam.